Brain function operates through the coordinated activation of neuronal assemblies. Graph theory predicts that scale-free topologies, which include "hubs" (superconnected nodes), are an effective design to orchestrate synchronization. Whether hubs are present in neuronal assemblies and coordinate network activity remains unknown. Using network dynamics imaging, online reconstruction of functiona...

A connected digraph of minimum degree δ is said to be maximally connected if the cardinality of every cutset is al least δ, and it is called superconnected if moreover every minimum disconnecting set F consists of the vertices adjacent to or from a given vertex not belonging to F . Let π be an integer, 0 ≤ π ≤ δ − 2, δ being the minimum degree of the digraph. In this work, we prove that if D ≤ ...

The societal diffusion of information and communications technologies (ICTs) remains starkly uneven at all scales. It is in the contemporary city that this unevenness becomes most visible. In cities, clusters and enclaves of ‘superconnected’ people, Ž rms and institutions often rest cheek-by-jowel with large numbers of people with non-existent or rudimentary access to communications technologie...

Connectivity in the developing hippocampus displays a functional organization particularly effective in supporting network synchronization, as it includes superconnected hub neurons. We have previously shown that hub network function is supported by a subpopulation of GABA neurons. However, it is unclear whether hub cells are only transiently present or later develop into distinctive subclasses...

In an exciting study in the December 4(th) issue of Science, Bonifazi and colleagues demonstrated the existence and importance of exceedingly rare but unusually richly connected cells in the developing hippocampus. Manipulating the activity of single GABAergic hub cells modulated network activity patterns, demonstrating their importance for coordinating synchronous activity.

The undirected graphs atoms were introduced independently Mader[21] and Watkins [28] in order to show that the connectivity of a connected undirected vertex-transitive is large. The directed graphs atoms were introduced by Chaty in [3]. The author obtained a structure Theorem for the atoms in the last case [9], showing that the connectivity of a connected vertex-transitive directed is large. Th...

Commentary Coordinated activation of neural networks is associated with most complex brain function in adults, and has been implicated in the maturation of neural circuits postnatally. Production of orchestrated neural population activity involves changes in cellular excitability, superimposed on synaptic and extra-synaptic communication characteristics that, in turn, require specific network a...